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This section includes 10 Mcqs, each offering curated multiple-choice questions to sharpen your Computational Fluid Dynamics knowledge and support exam preparation. Choose a topic below to get started.
1. |
The value of y+ at the intersection between the linear profile and log-law is ___________ |
A. | 20 |
B. | 5 |
C. | 30 |
D. | 11.63 |
Answer» E. | |
2. |
The value of y+ is 50. Which layer does it belong to? |
A. | Inertia dominated layer |
B. | Velocity defect layer |
C. | Log-law layer |
D. | Law of the wake layer |
Answer» D. Law of the wake layer | |
3. |
What is the range of y+ in the buffer layer? |
A. | 0 < y<sup>+</sup> < 5 |
B. | 5 < y<sup>+</sup> < 30 |
C. | 30 < y<sup>+</sup> < 500 |
D. | 10 < y<sup>+</sup> < 20 |
Answer» C. 30 < y<sup>+</sup> < 500 | |
4. |
Wall function cannot be used when ___________ |
A. | y<sup>+</sup><30 |
B. | y<sup>+</sup>>30 |
C. | y<sup>+</sup><20 |
D. | y<sup>+</sup>>20 |
Answer» B. y<sup>+</sup>>30 | |
5. |
What is the unit of y+? |
A. | y<sup>+</sup> is dimensionless |
B. | m |
C. | m<sup>2</sup> |
D. | 1 m |
Answer» B. m | |
6. |
What is shear velocity? |
A. | Square of the ratio of density to wall shear stress |
B. | Square root of the ratio of density to wall shear stress |
C. | Square of the ratio of wall shear stress to density |
D. | Square root of the ratio of wall shear stress to density |
Answer» E. | |
7. |
Let y be the distance from the wall, ut be the shear velocity and be the kinematic viscosity. Which of these equations define y+? |
A. | y<sup>+</sup>=y/u<sub>t</sub> |
B. | y<sup>+</sup>=u<sub>t</sub> /y |
C. | y<sup>+</sup>=(y u<sub>t</sub>)/ |
D. | y<sup>+</sup>=u<sub>t</sub>/y |
Answer» D. y<sup>+</sup>=u<sub>t</sub>/y | |
8. |
The concept of y+ is not used in which of these laws? |
A. | Law of the wall |
B. | Law of the wake |
C. | Log law |
D. | Linear law |
Answer» C. Log law | |
9. |
The value of y+ is used while finding ___________ |
A. | eddy kinematic viscosity for the turbulent boundary layers |
B. | mixing length for the turbulent boundary layers |
C. | eddy dynamic viscosity for the turbulent boundary layers |
D. | kinetic energy for the turbulent boundary layers |
Answer» C. eddy dynamic viscosity for the turbulent boundary layers | |
10. |
The value y+ is important only when we deal with ___________ |
A. | turbulent boundary layers |
B. | turbulent jets |
C. | free turbulent mixing layers |
D. | turbulent wakes |
Answer» B. turbulent jets | |